INTRODUCTION IN the following pages an attempt is made to relate what the author has seen, heard, and observed of the Mandaeans of Iraq and Iran. Observations were made over a number of years and furnish a considerable body of new evidence as to their customs, beliefs, cults, and magic. This evidence, we submit, is useful, not only to the student of anthropology, folk-lore, and ethnology, but to students of the history of religions, for the Mandaeans are what the doctor calls a case of arrested development. Their cults, which are regarded by them as more sacred than their books, and older, have been tenaciously retained; their ritual, in all its detail, most carefully preserved by a priesthood who regard a slip in procedure as a deadly sin. Segregated since the coming of Islam from those amongst whom they dwell by peculiarities of cult, custom, language, and religion, they have kept intact and inviolate the heritage which they had from their fathers.